Wide variations in the tannin and caffeine contents were observed in the tea cultivars collected from various locations in the world. In three groups of tea cultivars, the Assam group showed the widest variation, followed by the China group, while the Japan group showed a negligible variation. Fifteen cultivars with higher tannin content (＞25%) were screened only in the Assam group which belongs to C. sinensis var. assamica, while no cultivars with a higher tannin content were found in the China or Japan group which both belong to C. sinensis var. sinensis. Two cultivars with a lower caffeine content (＞2%) were screencd from the China group and seven from the Japan group. The variant cultivars in tannin or caffeine content are suitable tea breeding materials. On the basis of the tannin and caffeine contents, the Assam group (var. assamica) could be discriminated from the China and Japan groups (var. sinensis). It was obvious that the Japan group was a very homogeneous group in terms of tannin and caffeine contents. Some characteristics of the Assam cultivars were observed in the Cd cultivars of the China group which were collected in Darjeeling in India.